Solder bumps are widely used to connect a semiconductor die with a package substrate (e.g., flip-chip packaging) to form a “package.” Many solderable materials for solder bump applications including, for example, solder paste, have radioactive impurities that undergo radioactive decay, emitting alpha particles in the process. The emitted alpha particles can strike an integrated circuit (IC) device, such as a memory cell formed on a surface of the semiconductor die, changing the state of the IC device and resulting in potentially corrupted data. Even if the solderable material is an ultra-low alpha grade material
      (                  e        .        g        .            ,              0.001        -                  0.002          ⁢                                          ⁢                      particles                                          cm                2                            ·              hr                                            )    ,contamination from manufacturing operations associated with fabricating and/or packaging the semiconductor device can significantly increase alpha particle emission and, thus, increase data corruption of the IC device.
The description in this section is related art, and does not necessarily include information disclosed under 37 C.F.R. 1.97 and 37 C.F.R. 1.98. Unless specifically denoted as prior art, it is not admitted that any description of related art is prior art.